var name = "John"; // declaring a var variable
let age = 30; // declaring a let variable
const PI = 3.14; // declaring a const variable

console.log(name); // output: John
console.log(age); // output: 30
console.log(PI); // output: 3.14

name = "Jane"; // reassigned the value of name
age = 35; // reassigned the value of age

console.log(name); // output: Jane
console.log(age); // output: 35

// PI = 3; // this will throw an error because PI is a const variable and cannot be reassigned

const person = { // declaring a const variable that is an object
    name: "John",
    age: 30
};

person.age = 35; // mutating the value of age in the person object

console.log(person); // output: { name: "John", age: 35 }